Biased-core-current-transformer design method

THAT peculiar improvement in performance often occurred when a current-transformer core was divided into two parallel magnetic circuits, with different turns on each, has been well known for years, and the reasons for it have been understood in a general way. The calculation of performance of the transformer, however, has been a most baffling problem — one that could be worked out only on a tedious trial-and-error basis. The lack of a practical and straightforward method has been a serious handicap to full use of the method of construction, despite strong evidence that this method of construction, which is both practical and simple, would produce real improvement in performance.